Made available in DSpace on 2014-12-17T15:30:52Z (GMT). No. of bitstreams: 1 LucianaBA.pdf: 299762 bytes, checksum: b2ed4a69274795e7585d8ffaeab0f96d (MD5) Previous issue date: 2008-12-19 / The present experiment used cell culture to analyze the adhesion capacity of mouse mesenchymal bone marrow cells and rat periodontal ligament to different titanium surfaces. Grade II ASTM F86 titanium discs 15mm in diameter and 1.5mm thick were used and received 2 distinct surface treatments (polished and cathodic cage plasma nitriding). The cells were isolated from the mouse bone marrow and rat periodontal ligament and cultured in α-MEM basic culture medium containing antibiotics and supplemented with 10% FBS and 5% CO2, for 72 hours at 37?C in a humidified atmosphere. Subculture cells were cultured in a 24-well plate with a density of 1 x 104 cells per well. The titanium discs were distributed in accordance with the groups, including positive controls without titanium discs. After a 24-hour culture, the cells were counted in a Neubauer chamber. The results show that both the mouse mesenchymal bone marrow cells and rat periodontal ligament cells had better adhesion to the control surface. The number of bone marrow cells adhered to the polished Ti surface was not statistically significant when compared to the same type of cell adhered to the Ti surface treated by cathodic cage plasma nitriding. However a significant difference was found between the control and polished Ti groups. In relation to periodontal ligament cell adhesion, a significant difference was only found between the control and plasma-treated Ti surfaces. When comparing equal surfaces with different cells, no statistically significant difference was observed. We can therefore conclude that titanium is a good material for mesenchymal cell adhesion and that different material surface treatments can influence this process / O presente trabalho utilizou a cultura celular para analisar a capacidade de ades?o de c?lulas mesenquimais da medula ?ssea de camundongos e do ligamento periodontal de ratos a diferentes superf?cies de tit?nio. Para tanto, foram utilizados discos de tit?nio grau II ASTM F86 nas dimens?es de 15mm de di?metro por 1,5mm de espessura, os quais receberam diferentes tratamentos de superf?cie em 2 grupos distintos (polido e nitreta??o a plasma por gaiola cat?dica). As c?lulas foram isoladas da medula ?ssea de camundongos e do ligamento periodontal de ratos e cultivadas em meio de cultura meio b?sico α-MEM contendo antibi?ticos e suplementado com 10% de FBS, por 72 horas, em atmosfera ?mida com 5% de CO2 a 37?C. No subcultivo as c?lulas foram cultivadas em 1 placa de 24 po?os, na densidade de 1 x 104 c?lulas por po?o, onde os discos de tit?nio foram distribu?dos de acordo com os grupos, incluindo-se controles positivos sem os discos de tit?nio. Ap?s 24 horas de cultivo, as c?lulas foram submetidas a contagem em c?mara de Neubauer. Os resultados analisados mostraram que tanto as c?lulas mesenquimais da medula ?ssea de camundongos como as c?lulas do ligamento periodontal de ratos tiveram melhor ades?o ? superf?cie controle. O n?mero de c?lulas da medula ?ssea aderidas a superf?cie de Ti polido n?o foi estatisticamente significante quando comparado ao mesmo tipo celular aderido ? superf?cie de Ti tratada por plasma na configura??o de gaiola cat?dica, entretanto diferen?a significante foi encontrada entre o grupo controle e o grupo Ti polido. Com rela??o ? ades?o das c?lulas do ligamento periodontal, diferen?a significativa foi encontrada apenas entre as superf?cies controle e as superf?cies de Ti tratadas por plasma. No que diz respeito ?s compara??es entre superf?cies iguais com c?lulas diferentes, n?o foi observada nenhuma diferen?a estatisticamente significante. Portanto, conclui-se que o tit?nio ? um bom biomaterial para a ades?o de c?lulas mesenquimais e que as diferentes formas de tratamento de superf?cie dada ao material podem influenciar neste processo

Made available in DSpace on 2014-12-17T15:30:56Z (GMT). No. of bitstreams: 1 RodrigoAR_DISSERT.pdf: 1824764 bytes, checksum: fbfdfd8c2f743e113f6663106fda888b (MD5) Previous issue date: 2011-02-04 / In the last years, many scientific researches in implantology have been focused on alternatives that would provide higher speed and quality in the process of osseointegration. Different treatment methods can be used to modify the topographic and chemical properties of titanium surface in order to optimize the tissue-implant reactions by a positive tissue response. This study aimed to evaluate the adhesion and proliferation of mesenchymal cells from human periodontal ligament on two different titanium surfaces, using cell culture techniques. Grade II titanium discs received different surface treatments, forming two distinct groups: polished and cathodic cage plasma nitriding. Human periodontal ligament mesenchymal cells were cultured on titanium discs in 24-well cell culture plates, at a density of 2 x 104 cells per well, including wells with no discs as positive control. Data obtained by counting the cells that adhered to the titanium surfaces (polished group and cathodic cage group) and to the plastic surface (control group), in the 24, 48 and 72-hour periods after plating, were used to analyze cell adhesion and proliferation and to obtain the cell growing curve in the different groups. The data were submitted to nonparametric analysis and the differences between groups were compared by Kruskal-Wallis and Friedman statistical tests. No statistically significant differences were found in the cells counts between the groups (p>0.05). It was concluded that both treatments produced surfaces compatible with the adhesion and proliferation of human periodontal ligament mesenchymal cells / Nos ?ltimos anos, v?rias pesquisas cient?ficas em Implantodontia t?m buscado alternativas que proporcionem maior rapidez e qualidade no processo de osseointegra??o. Diferentes m?todos de tratamento podem ser utilizados para modificar as propriedades topogr?ficas e qu?micas da sua superf?cie do tit?nio, a fim de otimizar as rea??es tecido-implante atrav?s de uma resposta tecidual favor?vel. O presente trabalho teve como objetivo analisar a ades?o e prolifera??o de c?lulas mesenquimais de ligamento periodontal humano a diferentes superf?cies de tit?nio, atrav?s de t?cnicas de cultivo celular. Discos de tit?nio grau II receberam diferentes tratamentos de superf?cie, constituindo dois grupos distintos: polido e nitretado a plasma na configura??o de gaiola cat?dica. C?lulas mesenquimais obtidas do ligamento periodontal de dentes humanos h?gidos foram cultivadas sobre os discos de tit?nio em placas de cultivo de 24 po?os, na densidade de 2 x 104 c?lulas/po?o, incluindo po?os sem discos como controle positivo. Os dados obtidos das contagens das c?lulas aderidas ?s superf?cies de tit?nio (grupo polido e grupo gaiola cat?dica) e ? superf?cie pl?stica (grupo controle), nos intervalos de 24, 48 e 72 horas ap?s o plaqueamento, foram utilizados para analisar a ades?o e prolifera??o celular e obter a curva de crescimento celular nos diferentes grupos. Os dados foram submetidos a an?lises n?o param?tricas e as diferen?as entre os grupos foram comparadas pelos testes estat?sticos Kruskal-Wallis e Friedman. N?o foram encontradas diferen?as estat?sticas significativas nas contagens celulares entre os grupos estudados (p>0,05). Conclui-se que ambos os tratamentos produziram superf?cies compat?veis com ades?o e prolifera??o de c?lulas mesenquimais do ligamento periodontal humano

The evolutionary processes that shape individual variation in continuous behavioural traits remain poorly understood. While the emerging discipline of animal personality is providing increasing evidence that consistent individual differences in behaviour have significant fitness consequences, cognitive traits are yet to be explored in the same manner. My general objective in this thesis was twofold. First, I aimed to examine the ecological significance and fitness consequences of the cognitive trait innovative problem solving-performance, using a population of great tits (Parus major). Second, I aimed to explore the mechanisms underlying the functional significance of ‘exploration behaviour’ a captive measure of the reactive- proactive personality axis, focusing specifically on foraging and risk-taking behaviour. This two-trait approach was expected to shed light on whether personality and cognition simultaneously influence fundamental behaviours. By carrying out behavioural assays on birds temporarily held in captivity, I showed that success at solving a food-motivated problem was repeatable within individuals, consistent between two different tasks and independent of exploration behaviour. Problem-solving performance was positively related to clutch size and fledgling number, established when birds were released back into the wild. Furthermore, when rearing offspring, solvers had shorter working day lengths than non-solvers and foraged over smaller ranges without compromising either provisioning quantity or quality. However, solver females were also more likely to desert their broods than non-solvers and consequently there was little evidence to suggest that directional selection acted on problem-solving performance. In comparison to non-solvers, solver males were also found to be poorer at competing for limited food resources during the winter. Together these findings suggest that costs and benefits are associated with problem-solving performance, which together may act to maintain variation in this trait. My thesis also provides some of the first evidence that exploration behaviour is related to both foraging and risk-taking behaviour in the wild. In comparison to relatively slow explorers, fast exploring males were better competitors at feeders during the winter. Relatively fast and slow explorers also differed in a number of foraging behaviours during offspring provisioning, although not always in the direction predicted from captive work on other populations. Finally, while exploration behaviour was positively correlated with risk- taking behaviour amongst breeding females during incubation, it did not predict nest desertion in response to the risk associated with being trapped by field workers. Collectively these findings suggest that personality measured in captivity has specific but not general power to predict behaviour in the wild. An important facet of evolution is that natural selection is rarely likely to act on a single trait in isolation owing to correlations between traits. This thesis demonstrates how important behaviours in the wild can be simultaneously linked to multiple sources of consistent behavioural variation. It also represents the first large-scale investigation of how variation in a cognitive trait relates to natural behaviour, reproductive life-history variation and fitness in wild animals. Using this individual-based approach in a natural setting may prove to be a useful tool for understanding how selection acts on cognitive traits.

Submitted by PPG Odontologia (odontologia-pg@pucrs.br) on 2018-03-09T17:05:54Z No. of bitstreams: 1 ROSANGELA_MELLO_VIEIRA_DIS.pdf: 2509683 bytes, checksum: 029b2e55766a406fa01c070281169016 (MD5) / Approved for entry into archive by Tatiana Lopes (tatiana.lopes@pucrs.br) on 2018-03-14T12:03:02Z (GMT) No. of bitstreams: 1 ROSANGELA_MELLO_VIEIRA_DIS.pdf: 2509683 bytes, checksum: 029b2e55766a406fa01c070281169016 (MD5) / Made available in DSpace on 2018-03-14T12:12:44Z (GMT). No. of bitstreams: 1 ROSANGELA_MELLO_VIEIRA_DIS.pdf: 2509683 bytes, checksum: 029b2e55766a406fa01c070281169016 (MD5) Previous issue date: 2018-01-18 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior - CAPES / Introduction: The fracture of nickel titanium endodontic instruments may have a negative impact on the prognosis of the treatment, mainly because it blocks or prevents access to the root canal system in all its extension, compromising its modeling and sanification. Results from in vitro studies suggest that reciprocating motion can reduce the risks of torsion fracture and cyclic fatigue of NiTi instruments, compared to the continuous rotation movement. However, most of the studies that evaluate fracture resistance of instruments in reciprocating and rotational motion are in vitro studies, the generation of evidence of which is limited in comparison to the level of evidence generated by clinical studies in humans. Therefore, the present systematic review investigated whether the available evidence supports the hypothesis that reciprocating motion results in a lower clinical incidence of NiTi limb fracture as compared to rotational kinematics. Methodology: The PubMed, Embase, Isi Web of Science and Cochrane Library databases were searched until August 2017, without language restriction. In addition to the electronic searches, manual searches were made for additional references in specific chapters of relevant books in the area and also search in the gray literature. Based on the inclusion and exclusion criteria, two reviewers independently assessed the quality of each study based on the NewCastle Ottawa scale. The main exposure variable was the type of kinematics used to prepare the root canal (continuous or reciprocating) and the primary outcome variable was determined by the incidence of fracture of NiTi instruments in endodontic treatments. The incidence of fracture was recorded, having as unit of analysis: patients, teeth, instruments or channels. Other confounding variables collected included: country, year of publication, study design, type of system, group of teeth, number of sessions, operator and number of uses of NiTi instruments. The sources of heterogeneity were explored and the bi and multivariate meta logistic regression were performed to calculate the pooled estimates - odds ratios (OR) and 95% CI - for the incidence of instrument fracture, assessing the role of primary exposure and co- as moderators of the outcome. Results: Among the 737 articles initially identified, after the duplicates were removed, 39 comprised the final quantitative analysis, of which 32 reported the use of continuous rotation and 7 the use of reciprocating kinematics. Thirty-seven studies were included in the meta regression (N = 48,405 instruments). The aggregate clinical incidence of fracture of NiTi files was 2.43%, being 2.62% for continuous rotational movement and 0.4% for reciprocating kinematics. In the bivariate analysis, continuous rotational motion showed a greater incidence of fracture in relation to the reciprocating kinematics (OR = 6.39, 95% CI = 1.10-36.9), and the other associated covariates (p <0.05) with the incidence of fracture were: year of publication, operator and number of uses of the instruments. The multivariate models revealed that the number of uses of NiTi files in> 1 tooth (OR = 6.46, 95% CI = 1.42-29.3) and that general clinical operators (OR = 11.8, 95% CI = 1.49-93.5) were independently associated with a higher incidence of fracture of NiTi files, whereas kinematics was non-significant (OR = 1.56, 95% CI= 0.24-10, 0) after the settings. Conclusions: Available evidence from observational studies is limited but consistent, suggesting that reciprocating kinematics is associated with a lower incidence of fracture of NiTi files when compared to continuous rotation. In addition, the results revealed that other related clinical factors to the abilities of the operator,to the number of uses of the NiTi instruments, and to the advances in alloy composition as well as in the design of the files, have proved to be more relevant factors for fracture prevention than the type of kinematics employed. / Introdu??o: A fratura de instrumentos endod?nticos de n?quel tit?nio pode ter um impacto negativo no progn?stico do tratamento, sobretudo por bloquear ou impedir o acesso ao sistema de canais radiculares em toda sua extens?o, comprometendo a sua modelagem e sanifica??o. Resultados de estudos in vitro sugerem que o movimento reciprocante pode reduzir os riscos de fratura por tors?o e fadiga c?clica dos instrumentos de NiTi, comparado ao movimento de rota??o cont?nua. Ainda assim, a maioria dos estudos que avaliam a resist?ncia ? fratura de instrumentos no movimento reciprocante e rotat?rio s?o estudos in vitro, cuja gera??o de evid?ncias ? limitada em compara??o ao n?vel de evid?ncia gerada por estudos cl?nicos em humanos. Portanto, a presente revis?o sistem?tica investigou se a evid?ncia dispon?vel suporta a hip?tese de que o movimento reciprocante resulta em uma menor incid?ncia cl?nica de fratura de limas de NiTi, em compara??o com a cinem?tica rotat?ria. Metodologia: Foram pesquisadas as bases de dados PubMed, Embase, Isi Web of Science e Cochrane Library at? agosto de 2017, sem restri??o de idiomas. Al?m das buscas eletr?nicas foram realizadas buscas manuais por refer?ncias adicionais em cap?tulos espec?ficos de livros relevantes na ?rea e tamb?m busca na literatura cinza. Com base nos crit?rios de inclus?o e exclus?o, dois revisores avaliaram independentemente a qualidade de cada estudo com base na escala de NewCastle Ottawa. A principal vari?vel de exposi??o foi o tipo de cinem?tica empregada para o preparo do canal radicular (rotat?ria cont?nua ou reciprocante) e a vari?vel de desfecho prim?rio foi determinada pela incid?ncia de fratura de instrumentos de NiTi em tratamentos endod?nticos. A incid?ncia de fratura foi registrada, tendo como unidade de an?lise: pacientes, dentes, instrumentos ou canais. Outras vari?veis de confundimento coletadas incluiram: pa?s, ano de publica??o, desenho do estudo, tipo de sistema, grupo de dentes, n?mero de sess?es, operador e n?mero de usos dos instrumentos de NiTi. As fontes de heterogeneidade foram exploradas e a meta regress?o log?stica bi e multivariada foram realizadas para calcular as estimativas agrupadas ? odds ratios (OR) e 95%IC ? para a incid?ncia de fratura de instrumentos, avaliando o papel da exposi??o principal e das co-vari?veis, como moderadores do desfecho. Resultados: Entre os 737 artigos inicialmente identificados, ap?s remo??o das duplicatas, 39 compuseram a an?lise quantitativa final, dos quais 32 reportavam o uso de rota??o cont?nua e 7 o uso de cinem?tica reciprocante. Trinta e sete estudos foram inclu?dos na meta regress?o (N=48.405 instrumentos). A incid?ncia cl?nica agregada de fratura de limas de NiTi foi de 2,43%, sendo de 2,62% para o movimento rotat?rio cont?nuo e de 0,4% para a cinem?tica reciprocante. Na an?lise bivariada, o movimento rotat?rio cont?nuo demonstrou uma incid?ncia maior de fratura em rela??o ? cinem?tica reciprocante (OR=6,39, IC95%=1,10- 36,9), e as outras covari?veis associadas (p<0,05) com a incid?ncia de fratura foram: ano de publica??o, operador e n?mero de usos dos instrumentos. Os modelos multivariados revelaram que o n?mero de usos de limas de NiTi em >1 dente (OR=6,46, IC95%=1,42-29,3) e que operadores cl?nicos gerais (OR=11,8, IC95%=1,49-93,5) foram associados de modo independente com uma maior incid?ncia de fratura de limas de NiTi, enquanto que a cinem?tica demonstrou-se n?o-significante (OR=1,56, IC95%=0,24-10,0) ap?s os ajustes. Conclus?es: A evid?ncia dispon?vel, oriunda de estudos observacionais, ? limitada por?m consistente, sugerindo que a cinem?tica reciprocante est? associada com uma menor incid?ncia de fratura de limas de NiTi, quando comparada ao movimento de rota??o cont?nua. Al?m disso, os resultados revelaram que outros fatores cl?nicos relacionados ?s habilidades do operador, ao n?mero de usos dos instrumentos de NiTi, e aos avan?os na composi??o das ligas bem como no desenho das limas, demonstraram ser fatores mais relevantes para a preven??o da fratura do que o tipo de cinem?tica empregada.

Made available in DSpace on 2015-04-14T13:30:04Z (GMT). No. of bitstreams: 1 435511.pdf: 4163986 bytes, checksum: 37629882e85d83ed66d26ed9bed14b82 (MD5) Previous issue date: 2011-10-26 / In order to accelerate and improve the quality of the osseointegration process has recently been given emphasis to growth factors. Thus, this thesis was aimed to evaluate the use of growth hormone (GH) on osseointegration of titanium implants. This thesis is composed of two papers, the first chapter is a review of literature on the use of growth factors, and, in particular GH in the process of bone repair. The second chapter is an experimental study to evaluate the topical use of rhGH in the osseointegration of nanotexturized titanium implants inserted in the tibia of rabbits. We used 14 animals randomly divided into rhGH-treated group and control group. In the rhGH-treated group was administered 1 IU of rhGH in surgical defect immediately before the placement of each implant. In the control group was not used rhGH. Each animal received two implants in the left tibia. The animals were sacrificed at 14 and 42 days after surgery. The peri-implant regions were avaluated by transmission and reflection on optical microscopy (OM), to pull out biomechanical testing of implants and scanning electron microscopy (SEM). In all analyzes the rhGH-treated groups showed better performance than the control groups, especially at 14 days. MO at 14 days in the rhGH-treated group have histological characteristics of proliferative repair phase with new bone formation and also marked cortical reaction from the endosteum and periosteum and at 42 days, the bone tissue has a lamellar appearance. The control group at 14 days also has characteristics of the inflammatory and moderate proliferative new bone formation, and with 42 days the new bone does not have lamellar characteristics. In the pull-out testing of the rhGH-treated group showed tension of 59.26N/cm2 and 29.69 N/cm2 at 14 and 42 days respectively. The control group showed tension of 33.88 N/cm2 and 25.99 N/cm2 respectively. The implants analyzed in the SEM showed in the rhGH-treated group at 14 days greater amount of bone attached, but at 42 days there were no differences between groups. The findings in this experiment corroborate the literature, which observed that rhGH increases the speed and amount of newly peri-implanted bone, especially in the early stages of bone repair. Thus, this thesis concludes that topical application of rhGH in the region peri-implant area induces new bone formation. / Com o intuito de acelerar e melhorar a qualidade do processo de osseointegra??o, recentemente tem sido dado ?nfase aos fatores de crescimento. Logo, foi objetivo dessa Tese avaliar o emprego do horm?nio do crescimento (GH) na osseointegra??o de implantes de tit?nio. Esse trabalho ? composto de dois artigos, o primeiro artigo ? uma revis?o de literatura sobre o emprego dos fatores de crescimento, e, em especial o GH, no processo de reparo do tecido ?sseo. O segundo artigo ? um estudo experimental no qual se avaliou o uso t?pico do rhGH no processo de osseointegra??o de implantes de tit?nio nanotexturizados inseridos na t?bia de coelhos. Foram utilizados 14 animais divididos aleatoriamente em grupo teste e controle. No grupo teste foi aplicado 1 IU de rhGH no defeito cir?rgico imediatamente antes da coloca??o de cada implante. No grupo controle n?o foi aplicado o rhGH. Cada animal recebeu 2 implantes na t?bia esquerda. Os animais foram sacrificados em 14 e 42 dias depois da cirurgia. As regi?es periimplantares foram submetidas ? microscopia ?ptica (MO) de transmiss?o e de reflex?o, e os implantes ao ensaio biomec?nico de pull out e a microscopia eletr?nica de varredura (MEV). Em todas as an?lises realizadas o grupo teste apresentou desempenho superior ao controle, principalmente aos 14 dias. Na MO aos 14 dias o grupo teste possu?a caracter?sticas histol?gicas da fase proliferativa do reparo com acentuada neoforma??o ?ssea e tamb?m a forma??o de uma esp?cie de calo ?sseo sobre a cortical ?ssea externa, e aos 42 dias o tecido ?sseo possu?a aspecto lamelar. O grupo controle aos 14 dias possu?a ainda caracter?sticas da fase inflamat?ria e proliferativa com moderada neoforma??o ?ssea, e aos 42 dias o tecido ?sseo neoformado ainda n?o possu?a caracter?sticas lamelares. No ensaio de pull-out o grupo teste apresentou tens?o de 59,26 N/cm2 e 29,69 N/cm2 aos 14 e 42 dias respectivamente, enquanto o grupo controle apresentou tens?o de 33,88 N/cm2 e 25,99 N/cm2 aos 14 e 42 dias, respectivamente. Os implantes analisados no MEV demonstraram no grupo teste aos 14 dias maior quantidade de tecido ?sseo aderido, por?m aos 42 dias n?o se observaram diferen?as entre os grupos. Os achados no experimento corroboram com a literatura, em que se observa que o rhGH aumenta a velocidade e quantidade de osso periimplantar neoformado, principalmente em est?gios iniciais do reparo ?sseo. Com base na revis?o de literatura pesquisada e com os resultados do presente experimento, conclue-se que a aplica??o t?pica de rhGH na regi?o periimplantar acelera o processo de neoforma??o ?ssea. O grupo controle aos 14 dias possu?a ainda caracter?sticas da fase inflamat?ria e proliferativa com moderada neoforma??o ?ssea, e aos 42 dias o tecido ?sseo neoformado ainda n?o possu?a caracter?sticas lamelares. No ensaio de pull-out o grupo teste apresentou tens?o de 59,26 N/cm2 e 29,69 N/cm2 aos 14 e 42 dias respectivamente, enquanto o grupo controle apresentou tens?o de 33,88 N/cm2 e 25,99 N/cm2 aos 14 e 42 dias, respectivamente. Os implantes analisados no MEV demonstraram no grupo teste aos 14 dias maior quantidade de tecido ?sseo aderido, por?m aos 42 dias n?o se observaram diferen?as entre os grupos. Os achados no experimento corroboram com a literatura, em que se observa que o rhGH aumenta a velocidade e quantidade de osso periimplantar neoformado, principalmente em est?gios iniciais do reparo ?sseo. Com base na revis?o de literatura pesquisada e com os resultados do presente experimento, conclue-se que a aplica??o t?pica de rhGH na regi?o periimplantar acelera o processo de neoforma??o ?ssea.

Made available in DSpace on 2014-12-17T15:41:40Z (GMT). No. of bitstreams: 1 AnaCPC.pdf: 1447913 bytes, checksum: 8f65c2f6df911f6db297163eb551fb69 (MD5) Previous issue date: 2008-02-29 / Conselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico / The metalic oxides have been studies due to differents applications as materials semiconductor in solar cells, catalysts, full cells and, resistors. Titanium dioxide (TiO2) has a high electric conductivity due to oxygen vacancies. The Ce(SO4)2.2H2O doped samples TiO2 and TiO2 pure was obtained sol-gel process, and characterized by X-ray diffractometry,thermal analysis, and impedance spectroscopy. The X-ray diffraction patterns for TiO2 pure samples shows at 700?C anatase phase is absent, and only the diffraction peaks of rutile phase are observed. However, the cerium doped samples only at 900?C rutile in the phase present with peaks of cerium dioxide (CeO2). The thermal analysis of the TiO2 pure and small concentration cerium doped samples show two steps weight loss corresponding to water of hydration and chemisorbed. To larger concentration cerium doped samples were observed two steps weight loss in the transformation of the doped cerium possible intermediate species and SO3. Finally, two steps weight loss the end products CeO2 and SO3 are formed. Analyse electric properties at different temperatures and concentration cerium doped samples have been investigated by impedance spectroscopy. It was observed that titanium, can be substituted by cerium, changing its electric properties, and increased thermal stability of TiO2 anatase structure / Os ?xidos met?licos t?m sido muito estudados devido suas diversas aplica??es como materiais semicondutores em c?lulas solares, catalisadores, c?lulas combust?veis e resistores. O Di?xido de Tit?nio possui uma alta condutividade el?trica devido ?s suas vac?ncias de oxig?nio. Amostras de TiO2 puro, obtidas pelo m?todo sol-gel e dopadas com solu??es de Ce(SO4)2.2H2O, foram analisadas atrav?s de difratometria de raios-X, an?lise t?rmica e espectroscopia de imped?ncia. Atrav?s dos difratogramas de raios-X observou-se a transi??o completa das fases anat?sio-rutilo, para a amostra do TiO2 puro a partir de 700?C. Entretanto, para as amostras dopadas, essa transi??o s? ? completa a partir de 900?C, aparecendo picos correspondentes ao ?xido de c?rio. Atrav?s da an?lise t?rmica se observou uma perda de massa, para o TiO2 puro e dopado com a menor concentra??o de c?rio, correspondente ? desidrata??o e a ?gua quimissorvida. Para as amostras dopadas em uma maior concentra??o, foram observados dois est?gios de perda de massa, devido a decomposi??o do dopante em intermedi?rios e SO3. Essas amostras apresentaram mais duas perdas de massa devido a forma??o do CeO2 e SO3. A partir da espectroscopia de imped?ncia analisou-se as propriedades el?tricas das amostras em fun??o da temperatura de calcina??o e em fun??o da concentra??o do dopante. Tamb?m foi observado que o c?rio, por ter a capacidade de substituir o tit?nio na sua estrutura cristalina, modifica suas propriedades el?tricas e tem o poder de estabiliz?-lo termicamente em certas temperaturas

Combined cycle power plants haven becoming one of the mainstream power plants in the twenty-one century. The emergence of high 600¢J exhaust temperature of the gas turbine, due to the recent rapid enhancement of aerospace material and blade cooling methods, upgrades the gas turbine from low efficiency dual pressure non-reheat unit to high efficiency triple pressure reheat combined cycle power plants. In addition, the increase of turbine inlet temperature by 10~15¢J every year leads to the renewal of the advanced models gas turbine less than ten years. There are three-turbine inlet temperature (TIT) definitions in the gas turbine: (1) TA defines firing temperature as the mass flow mean total temperature before the first-stage stationary diagram edge plane.( Westinghouse or MHI product) (2) TB defines fire temperature as the mass flow mean total temperature at the first-stage nozzle trailing edge plane, ( GE product). (3) TC defines ISO firing temperature; it is a stoichiometric combustion temperature. It is not a physical temperature. ( Siemens ¡® Alstom ABB product). This study shows how to calculate compressor inlet mass flow balance, turbine power balance and heat balance on the combustion chamber system. In order to prove correctness of the balance equation, the data are taken from the heat balance diagram and acceptance test of Nan-pu power station combined cycle. The result shows that the study is sultable for application of the optimum analysis for CCPP operation performance. This type of combined cycle power plant suits not only for the base-load but also for the cycling-load operation.

Made available in DSpace on 2014-12-17T14:06:59Z (GMT). No. of bitstreams: 1 NarayannaMF_DISSERT.PDF: 4537293 bytes, checksum: 5d2c22b8b17b69adbe02ea6e28e15de6 (MD5) Previous issue date: 2011-07-29 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior / Microalloyed steels constitute a specific class of steel with low amount of carbon and microalloying elements such as Vanadium (V), Niobium (Nb) and Titanium (Ti). The development and application of microalloyed steels and steels in general are limited to the handling of powders with particles of submicron or nanometer dimensions. Therefore, this work presents an alternative in order to construction of microalloyed steels utilizing the deposition by magnetron sputtering technique as a microalloying element addiction in which Ti nanoparticles are dispersed in an iron matrix. The advantage of that technique in relation to the conventional metallurgical processes is the possibility of uniformly disperse the microalloying elements in the iron matrix. It was carried out deposition of Ti onto Fe powder in high CH4, H2, Ar plasma atmosphere, with two deposition times. After the deposition, the iron powder with nanoparticles of Ti dispersed distributed, were compacted and sintered at 1120 ? C in resistive furnace. Characterization techniques utilized in the samples of powder before and after deposition of Ti were Granulometry, Scanning Electron Microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX) and X-ray diffraction (DRX). In the case of sintered samples, it was carried out characterization by SEM and Vickers Microhardness assays. The results show which the deposition technique by magnetron sputtering is practicable in the dispersion of particles in iron matrix. The EDX microanalysis detected higher percentages of Ti when the deposition were carried out with the inert gas and when the deposition process was carried out with reactive gas. The presence of titanium in iron matrix was also evidenced by the results of X-ray diffraction peaks that showed shifts in the network matrix. Given these results it can be said that the technique of magnetron sputtering deposition is feasible in the dispersion of nanoparticles of iron matrix in Ti. / Os a?os microligados constituem uma classe espec?fica de a?o com baixos teores de carbono e elementos microligantes, como: van?dio (V), ni?bio (Nb) e tit?nio (Ti). O desenvolvimento e aplica??o dos a?os microligados, e de a?os em geral, est?o limitados ? manipula??o dos p?s com part?culas de dimens?es submicrom?tricas ou mesmo nanom?tricas. Mediante isto, este trabalho apresenta uma t?cnica alternativa para a fabrica??o de a?os microligado empregando a deposi??o por magnetron sputtering, como fonte de adi??o de elemento microligante na forma de nanopart?culas de tit?nio dispersa em matriz de ferro. A vantagem dessa t?cnica em rela??o aos processos metal?rgicos convencionais ? a possibilidade de dispersar uniformemente o elemento microligante na matriz de ferro. Foram realizadas deposi??es de Ti sobre p? de ferro em atmosfera de CH4, H2, Ar, com dois tempos de deposi??o diferentes. Ap?s as deposi??es, o p? de ferro com nanopart?culas de Ti dispersamente distribu?das, foram compactados e sinterizados a 1120?C em forno resistivo. As t?cnicas de caracteriza??o utilizadas nas amostras de p? de ferro antes e ap?s a deposi??o de Ti foram granulometria, microscopia eletr?nica de varredura (MEV), energia dispersiva de raios X (EDX) e difra??o de raios X (DRX). Para as amostras sinterizadas utilizou-se a caracteriza??o por microscopia eletr?nica de varredura (MEV) e ensaio de microdureza Vickers. A microan?lise por EDX detectou percentuais maiores de Ti para as deposi??es em atmosfera de g?s inerte em rela??o ?s deposi??es em atmosfera de g?s reativo. A presen?a de tit?nio na matriz de ferro tamb?m foi evidenciada pelos resultados da difra??o de raios-X que apresentaram deslocamentos nos picos da rede da matriz. Diante desses resultados pode-se afirmar que a t?cnica de deposi??o por magnetron sputtering ? vi?vel na dispers?o de nanopart?culas de Ti em matriz de ferro.

Made available in DSpace on 2014-12-17T14:07:01Z (GMT). No. of bitstreams: 1 AndreaMAA.pdf: 2205764 bytes, checksum: 63a73bc4d3b5aa4b2d1dd4cc4bb34040 (MD5) Previous issue date: 2006-09-01 / The partial fixed prosthodontics restoration is used to rehabilitate form and function of partial or total compromised teeth, having to remain permanently joined to remainder tooth. The most useful material on prosthodontics is the feldspar porcelain, commercialized as aluminosilicate powders. Dental porcelains are presented with limited mechanical properties to rehabilitate extensive spaces. The association with Ni-Cr metallic systems (metal-ceramic system) allows that the metallic substructure compensates the fragile porcelain nature, preserving the thermal insulation and aesthetics desirable, as well as reducing the possibility of cracking during matication efforts. Cohesive flaws by low mechanical strength connect the metallic substructure to the oral environment, characterized by a electrolytic solution (saliva), by aggressive temperature, pH cyclic changes and mechanical requests. This process results on ionic liberation that could promote allergic or inflammatory responses, and/or clinical degradation of ceramometal system. The aim of this study was to evaluate the presence of an intermediate titanium layer on the microscopic fracture behavior of porcelains on ceramometal systems. Plasma deposition of titanium films result in regular passivating oxide layers which act as barriers to protect the metallic substrate against the hazardous effects of corrosive saliva. Tribocorrosion tests were performed to simulate the oral environment and mechanical stress, making it possible the early detection of crack formation and growth on metal-ceramic systems, which estimate the adherence between the compounds of this system. Plain samples consisting of dental feldspar porcelain deposited either onto metallic substrates or titanium films were fired and characterized by scanning electron microscopy. The result showed that the titanium film improved the adherence of the system compared to conventional metal-ceramic interfaces, thus holding crack propagation / A pr?tese parcial fixa ? empregada na reabilita??o da forma e fun??o de dentes parcial ou totalmente comprometidos, devendo permanecer unida permanentemente aos remanescentes dent?rios. O material mais utilizado na confec??o de pr?teses odontol?gicas ? a porcelana feldsp?tica, disponibilizada sob a forma de p? de aluminossilicatos. As porcelanas odontol?gicas apresentam-se com propriedades mec?nicas limitadas para a reabilita??o em monobloco de espa?os ed?ntulos extensos. A associa??o com sistemas met?licos de n?quel-cromo (sistema metalocer?mico) permite que a infra-estrutura met?lica compense a natureza fr?gil da porcelana, preservando-se a isola??o t?rmica e est?tica desej?veis, bem como reduzindo a possibilidade do desenvolvimento de trincas durante os esfor?os mastigat?rios. Falhas coesivas por baixa resist?ncia mec?nica da porcelana, comunicam a estrutura met?lica com o ambiente oral, caracterizado pela presen?a de uma solu??o eletrol?tica (saliva), pela agressividade das varia??es c?clicas de temperatura, pH e das solicita??es mec?nicas. Este processo resulta na libera??o de ?ons met?licos que podem desencadear respostas al?rgicas ou inflamat?rias, e /ou na degrada??o cl?nica precoce do sistema metalocer?mico. Este trabalho teve por objetivo avaliar o efeito da presen?a de uma camada intermedi?ria de tit?nio sobre o comportamento fratogr?fico, microsc?pico de porcelanas em sistemas metalocer?micos. A aplica??o por plasma de um filme fino de tit?nio, gera uma camada ?xida passivante regular que tende a proteger o substrato met?lico contra os efeitos corrosivos da saliva. Ensaios tribocorrosivos foram realizados para simular o ambiente oral, detectando precocemente a forma??o de trincas no sistema metalocer?mico, o que qualifica a ader?ncia entre os componentes do referido sistema. Foram produzidas amostras planas nas quais suspens?es de porcelana feldsp?tica odontol?gica foram depositadas e queimadas sobre substratos met?licos modificados por filme fino de tit?nio, comparando-as com o sistema metalocer?mico convencional. O sistema de teste apresentou melhores resultados, caracterizando-se pelo menor n?mero de tra?os de fratura superficial adjacentes ? ?rea de ensaio

Made available in DSpace on 2014-12-17T14:07:06Z (GMT). No. of bitstreams: 1 JulioCPB_TESE.pdf: 3654750 bytes, checksum: 7f67c8015c3dc4175f16964a07eacd69 (MD5) Previous issue date: 2011-04-29 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior / Plasma diagnostics by Optical Emission Spectroscopy were performed for electrical discharge in three gas mixture respecting the combinations z N2 y Ar x H2, z N2 y Ar x O2 e z N2 y Ar x CH4, in which the indexes z and y systematically vary from 1 to 4 and x varies from 0 to 4, every one has dimension SCCM, resulting in 80 combinations. From the all obtained spectrums, the species CH (387,1 nm), N2+ (391,4 nm), H&#946; (486,1 nm), H&#945; (656,3 nm), Ar (750,4 nm), O (777,4 nm) e O (842,6 nm) were analyzed because of their abundance and importance on the kinetic of reaction from the plasma to surface, besides their high dependences on the gases flows. Particularly interesting z, y and x combinations were chosen in order to study the influence of active species on the surface modification during the thermochemical treatment. From the mixtures N2 Ar O2 e N2 Ar CH4 were chosen three peculiar proportions which presented luminous intensity profile with unexpected maximum or minimum values, denominated as plasma anomaly. Those plasma concentrations were utilized as atmosphere of titanium treatment maintaining constant the control parameters pressure and temperature. It has been verified a relation among luminous intensity associated to N2+ and roughness, nanohardness and O atoms diffusion into the crystalline lattice of treated titanium and it has been seen which those properties becomes more intense precisely in the higher points found in the optical profile associated to the N2+ specie. Those parameters were verified for the mixture which involved O2 gas. For the mixture which involves CH4 gas, the relation was determinate by roughness, number of nitrogen and carbon atoms diffused into the titanium structure which presented direct proportionality with the luminous intensity referent to the N2+ and CH. It has been yet studied the formation of TiCN phases on the surface which presented to be essentially directly proportional to the increasing of the CH specie and inversely proportional to the increasing of the specie N2+ / Diagn?sticos de plasma por Espectroscopia de Emiss?o ?ptica foram realizados para descarga el?trica em tr?s misturas gasosas, dentro das seguintes combina??es: z N2 y Ar x H2, z N2 y Ar x O2 e z N2 y Ar x CH4, com os ?ndices z e y variando sistematicamente de 1 a 4 e x de 0 a 4, todos com dimens?o de SCCM, resultando em 80 combina??es. Dos espectros obtidos, foram analisadas as esp?cies CH (387,1 nm), N2+ (391,4 nm), H&#946; (486,1 nm), H&#945; (656,3 nm), Ar (750,4 nm), O (777,4 nm) e O (842,6 nm) por serem mais abundantes e importantes na cin?tica de rea??o do plasma ? superf?cie, al?m de suas altas depend?ncias dos fluxos de g?s. Foram escolhidas combina??es z, y e x, particularmente interessantes para estudar a influ?ncia das esp?cies ativas na modifica??o da superf?cie durante o tratamento termoqu?mico. Das misturas N2 Ar O2 e N2 Ar CH4 foram escolhidas tr?s propor??es peculiares que apresentavam perfis de intensidade luminescente com m?ximos ou m?nimos inesperados classificados aqui como anomalias de plasma. Essas concentra??es de plasma foram utilizadas como atmosfera de tratamento de amostras de tit?nio, mantendo-se constante os par?metros press?o e temperatura. Verificou-se rela??o entre intensidade luminosa associada ? esp?cie N2+ e a rugosidade, nanodureza e a difus?o do oxig?nio na rede cristalina do tit?nio tratado e viu-se que essas propriedades se intensificam precisamente nos pontos de m?ximo encontrados no perfil ?ptico dessa esp?cie. Esses par?metros foram verificados para mistura que envolvia o g?s O2. Para a mistura em que se fez presente o g?s CH4, a rela??o foi determinada por meio da rugosidade, n?mero de ?tomos de nitrog?nio e carbono difundidos no tit?nio, que apresentou proporcionalidade direta com a intensidade luminosa referente ?s esp?cies N2+ e CH. Ainda foi estudada a forma??o de fases TiCN na sua superf?cie, que essencialmente se mostra diretamente proporcional ao crescimento da esp?cie CH e inversamente proporcional ao crescimento da esp?cie N2+